Re: Spectrum Analyser TR4172
Incidentally, after checking some date codes on some components, I did not see anything newer than '83. So for the record, this is a Takeda Riken branded TR4172 likely made in '83. It finally succumbed to the lead rot in the 1st mixer in 2021, just as Jeremy described (see post #35 for the ugliness). I was investigating the major loss in sensitivity a few weeks ago and this is exactly what I found. Thankfully I was able to perform major surgery on the mixer and repair the problem. It seems mechanically solid now, and is certainly working electronically, but I don't know how long that will last. Hopefully at least another 38 years. My guess is that it isn't tuned as well as it was originally though... but I am not in need of perfection.
73,
Matt
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